On pretending to not listen to a language one is learning

I've noticed a tendency when learning another language to "not-listen." This is a defensive act.

When learning a language, one must listen. But listening studiously is an intensive activity  and one that may become obvious. You may become suddenly involved in a conversation that you only wanted to hear  one that you were not prepared to enter.

While it's not as obvious as staring, listening can be apparent. You don't notice this until it's uncomfortable. And when people notice that you're listening and speak to you as if you understand, it can be awkward.
When you have to explain to too many people that you don't speak the language very well, it becomes tedious.